The purpose of this study was to investigate changes in the upper and lower lip vermilion areas and the relevant factors in mandibular prognathism patients treated with orthognathic surgery.
The samples were diagnosed as a mandibular protrusion and collected from mandibular prognathism patients before treatment with orthognathic surgery from 2000 to 2007.
Subjects with congenital disease including cleft lip and palate, syndrome and severe facial asymmetry with jaw deviation were excluded. All subjects were divided into two groups by surgical procedure. Eighteen and 16 patients underwent mandibular setback surgery (one-jaw group) and two-jaw surgery (two-jaw group), respectively. Lateral cephalograms and standardized frontal facial photographs were taken before and after surgery and used for the analysis. Cephalometric analysis of the changes of skeletal and dentoalveolar structures was conducted.
Upper and lower lip vermilion areas were measured by using NIH Image software (National Institute of Health, Bethesda, MD, USA). A paired t-test was used to identify significant changes in skeletal components and lip vermilion areas before and after surgery. Pearson correlation analysis was also used to discriminate skeletal changes responsible for lip vermilion changes before and after surgery.
The following results were obtained.
1. In the one-jaw group, the lower lip vermilion area exhibited a decreasing tendency, whereas the upper lip vermilion area was almost invariable. Thus, the ratio of vermilion area (upper lip vermilion area/lower lip vermilion area) showed a slight increase.
2. In the two-jaw group, the upper vermilion area exhibited an increasing tendency, while the lower vermilion area was almost unchanged. As a result, the ratio of vermilion area increased similarly to that in the one-jaw group.
3. In the one-jaw group, a significant negative correlation was found between overjet and lower lip vermilion area.
4. In the two-jaw group, a significant positive correlation was found between changes in vertical position of Point A and upper vermilion area. Moreover, there was a significant negative correlation between changes in FMA and upper vermilion area.
These results suggested that although the ratio of vermilion area increased in the one-jaw and two-jaw groups after orthognathic surgery, the mechanism of lip morphological improvement was quite different in the two groups. It is also considered that the counter-clockwise rotation of the mandible following upward movement of the maxilla achieved by two-jaw surgery affects the change in upper lip vermilion area.

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The purpose of this study was to assess the postoperative stability of the distal segment and the condylar head of the mandible in eleven follow-up patients after intraoral vertical ramus osteotomy (IVRO). Retrospective radiographic assessments of horizontal and vertical changes of point B on distal segment and preoperative amount of overbite were performed based on lateral cephalograms. In addition, the position of the condylar head and the inclination angle of the condylar process were also analyzed by lateral panoramic temporomandibular joint projection photographs and computer tomography.
The results were as follows:
1. The distal segment of the mandible tended to move in the postero-inferior direction in five cases, four of which were open-bite.
2. The five cases tended to show a delay in adaptation of the condylar head in the grenoid fossa postoperatively. In particular, two cases in whom the distal segment showed large clockwise rotation, possessed a shallow inclination angle of the condylar process.
The results of this study suggest that the stability of the distal segment after IVRO depends on the preoperative amount of overbite before operation. The relation between the inclination angle of the condylar process and postoperative stability, however, was not elucidated.

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The amount of postoperative bone resorption after genioplasty was studied in 13 patients. The subjects of this study were 4 patients who underwent genioplasty alone, and 5 who underwent genioplasty combined with other techniques for correcting skeletal Class II and Class III deformities.
Large advancement genioplasties were performed on 13 patients by horizontal osteotomy of the inferior border of the mandible, with preservation of a musculoperiosteal pedicle to the advanced genial segment. Preoperative, immediate postoperative, and long-term follow-up lateral cephalometric radiographs were retrospectively analyzed to evaluate the osseous changes of the chin. We examined the correlation between bone resorption and the degree of advancement, the degree of mandible movement, the height of the genial segment, and the distance from the existing bone to the genial segment. The results showed a correlation between bone resorption and the distance from existing bone to the genial segment. This suggests that the supply of blood between existing bone and the genial segment has an influence on bone resorption.

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Hemifacial microsomia (HFM) is characterized by unilateral underdevelopment of facial bones and soft tissues originating from the first and second branchial arches. In this article, we report an adolescent HFM patient treated with a functional appliance to facilitate mandibular growth.
The patient was a 7-year 1-month-old boy with the chief complaint of open bite and facial asymmetry. He had Pruzansky Grade II deformity of the mandible. The overjet was 7.0 mm, the overbite was -5.0 mm, and Hellman's dental age was IIC. The left lower second premolar was congenitally missing and the left lower first molar showed a 90-degree mesio-buccal rotation. The postero-anterior cephalometric analysis revealed that the mandible was shifted to the left side and the occlusal plane was tilted upward on the left side. The lateral cephalometric analysis showed a small and distally-located mandible with clockwise rotation. Prior to orthognathic treatment started at 15 years old, the first phase of treatment was initiated with a functional appliance and headgear for a period of 1 year and 10 months at 12 years 10 months old.
During the initial 4 years of treatment from the first consultation at 7 years 1 month old, the amount of occlusal plane inclination and lateral shift of the mandible increased due to a lack of patient cooperation. Nevertheless, use of the functional appliance improved the facial asymmetry due to lateral shift of the mandible. On the lateral cephalogram, a remarkable mandibular growth was found on the asymptomatic left side of the mandible.

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This study examined the long-term changes in tongue and pharyngeal airway morphology of a 7-year-old girl. She had a severe vertical jaw deformity with a 17-mm anterior open bite due to macroglossia. She had already undergone surgical reduction glossectomy two times prior to the initial consultation in our clinic.
Tooth extraction and orthognathic surgery were avoided to maintain sufficient oral cavity volume for the large tongue.
After 3-year multi-bracket system (MBS) treatment, the malocclusion and masticatory dysfunction were corrected appropriately. Moreover, cephalometric evaluation during the orthodontic treatment showed no morphological disharmony of the tongue and pharyngeal airway. However, the tongue position displaced backward due to the correction of the open bite.
In this patient, sleep-disorder breathing as a result of the reduction in size of the pharyngeal airway might occur in the future. Therefore, long-term follow-up observation is required for preventing morphological changes in the pharyngeal airway and relapse due to macroglossia.

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第21回特定非営利活動法人日本顎変形症学会総会　プログラム・抄録号（第21巻2号）に訂正がありましたのでお知らせします。
示説100　筆頭演者の誤記
【誤】 高野　伸夫
【正】 須賀賢一郎

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